The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Internal combustion engines used to power a vehicle combust fuel in the presence of air to produce power. The combustion of the fuel produces exhaust that contains various gases and particulate matter (PM). The exhaust may be treated in an exhaust system to reduce concentrations of certain constituent gases and the PM. For example, a catalytic converter may reduce the concentration of gases such as carbon monoxide (CO) and hydrocarbons (HC) in the exhaust. The PM may be filtered from the exhaust by a PM filter.
Over time, PM filtered from the exhaust accumulates within the PM filter and begins to restrict the flow of exhaust. PM that has accumulated within the PM filter may be removed by a process referred to as regeneration. During regeneration, PM within the PM filter is combusted. Typically, regeneration is accomplished by raising the temperature of the PM filter above a regeneration temperature. At temperatures above the regeneration temperature, PM accumulated within the PM filter will begin to combust. The temperature of the PM filter is held above the regeneration temperature for a period until a desired amount of the PM is combusted.
In some regeneration processes, a hydrocarbon injection (HCl) system injects fuel into the exhaust and the fuel is combusted in the catalytic converter to produce heat for raising the temperature of the PM filter above its regeneration temperature. Control systems have been developed to control the amount of heat produced by controlling the amount of fuel delivered to the exhaust. Diagnostic systems have been developed to detect problems with the operation of the HCl system. For example, such systems may detect problems with a fuel injector used to inject the desired amount of fuel, such as a sticking problem or a clogging problem.
When a problem is detected, a fault code may be stored in memory and remedial action may be initiated. For example, a malfunction indicator lamp (MIL) may be illuminated to alert a driver of the problem. Regeneration may be suspended and/or a remedial control strategy for supplying fuel to the exhaust during regeneration may be initiated.